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GCSEBIOLOGY

Answer all questionsAnswer questions in the space providedAll working must be shownDo all rough work in this book. Cross out any rough work you don't want to be marked

B1

CELL BIOLOGY

TEST 2

Score (%)Mark

MaterialsFor this paper you must have:

RulerPencil, Rubber, Protractor and CompassScientific calculator, which you are expected to use when appropriate

Instructions

InformationThe marks for the questions are shown in brackets

Name:

Date:

AQA - COMBINED SCIENCE

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The image below shows some muscle cells from the wall of the stomach, as seen through a lightmicroscope.

1

(a) Describe the function of muscle cells in the wall of the stomach.

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(2)

(b) The figure above is highly magnified.

The scale bar in the figure above represents 0.1 mm.

Use a ruler to measure the length of the scale bar and then calculate the magnification ofthe figure above.

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Magnification = _______________ times

(2)

(c) The muscle cells in Figure above contain many mitochondria.

What is the function of mitochondria?

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(2)

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(d) The muscle cells also contain many ribosomes. The ribosomes cannot be seen in thefigure above.

(i) What is the function of a ribosome?

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(1)

(ii) Suggest why the ribosomes cannot be seen through a light microscope.

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(1)

(Total 8 marks)

Figure 1 shows one type of white blood cell.

Figure 1

2

(a) What is structure A?

Tick one box.

Cell membrane

Cell wall

Cytoplasm

Nucleus

(1)

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(b) White blood cells help to defend the body against pathogens.

How do the white blood cells do this?

Tick three boxes.

Clone pathogens

Engulf pathogens

Produce antibiotics

Produce antibodies

Produce antitoxins

Produce toxins

(3)

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Measles is a serious disease. A person can die from measles.

Figure 2 shows the number of cases of measles in England and Wales between 2012 and 2015

Figure 2

(c) Use Figure 2 to calculate the decrease in the number of cases of measles between 2012and 2015

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Answer = ______________________ cases

(2)

(d) Suggest one reason for the decrease in the number of cases of measles between 2012and 2015

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(1)

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(e) Antibiotics cannot be used to treat measles.

Suggest why.

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(1)

(f) Gonorrhoea is a disease caused by a bacterium.

Gonorrhoea can be treated with antibiotics.

Give one other way to control the spread of gonorrhoea.

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(1)

A scientist investigated how effective different antibiotics were at killing gonorrhoea bacteria.

This is the method used.

1. Grow gonorrhoea bacteria on agar in a Petri dish.2. Place one paper disc soaked in water onto the agar.3. Place four other paper discs, each soaked in a different antibiotic, A, B, C, and D, onto the

agar.4. Use the same sized paper discs and the same concentration of each antibiotic.5. Incubate the Petri dish for 3 days.

Figure 3 shows the scientist’s results.

A clear area around the disc means the antibiotic has killed the bacteria.

Figure 3

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(g) Give one control variable the scientist used.

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(1)

(h) Suggest why one disc was soaked in water.

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(1)

(i) Which antibiotic in Figure 3 would be the best to treat gonorrhoea?

Give a reason for your answer.

Antibiotic ___________________________________________________________

Reason ____________________________________________________________

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(2)

(Total 13 marks)

A student investigated the effect of different concentrations of sugar solution on pieces of potato.


1. Cut three pieces of potato to the same length.2. Dry each piece on a paper towel.3. Weigh each piece.4. Place each piece in a different concentration of sugar solution.5. Leave all three pieces for 2 hours.6. Remove the three pieces of potato from the solutions.7. Dry each piece on a paper towel.8. Measure the length and mass of each piece of potato.

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Figure 1 shows how the investigation was set up.

Figure 1

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(a) Why did the student dry each piece of potato before weighing it?

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(1)

(b) What two changes would you expect in the potato in tube A after 2 hours?

Tick two boxes.

Breaks into pieces

Decrease in hardness

Decrease in size

Increase in mass

Increase in length

(2)

(c) Complete the sentences.

Water moves into and out of cells by a process called ____________________ .

Water would move ____________________ the potato cells in tube A.

The solution outside the potato in tube A is at a ____________________

concentration than the solution inside the potato cells.

(3)

(d) The potato in tube B did not change.

Give one conclusion that can be made from this observation.

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(1)

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(e) Figure 2 shows the root of a germinating seed.

Figure 2

Describe two ways the root is adapted to absorb water efficiently.

1. _________________________________________________________________

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2. _________________________________________________________________

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(2)

(Total 9 marks)

A student investigated the effect of different concentrations of sugar solution on pieces of carrot.


1. Weigh five pieces of carrot.2. Place each piece into a different tube.3. Into each tube add 20 cm3 of water or one of the sugar solutions as shown in Figure 14. Leave the apparatus for 2 hours.5. Remove the carrot and dry each piece on paper towel.6. Reweigh each piece.7. Calculate the percentage (%) change in mass of each piece.

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Figure 1 shows how the investigation was set up.

Figure 1

The table below shows the results.

Concentration of sugarsolution in mol/dm3

Percentage (%) change inmass

0.0 +24

0.2 +12

0.4 +1

0.6 −8

0.8 −15

(a) Suggest why the student calculated the percentage (%) change in mass of each piece ofcarrot.

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(1)

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(b) Complete Figure 2 using the results in the table above

• Choose a suitable scale and label for the y-axis.• Plot the results.• Draw a line of best fit.

Figure 2

(4)

(c) Estimate the concentration of sugar solution inside the carrot cells.

Use your completed graph on Figure 2

Concentration = _______________________ mol/dm3

(1)

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(d) Explain why the mass of the carrot in the 0.6 mol/dm3 sugar solution changed.

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(4)

(e) The student repeated the investigation using boiled pieces of carrot.

The pieces of carrot did not change in mass.

Suggest why.

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(1)

(Total 11 marks)

This question is about stem cells.

(a) Give one place in a plant where stem cells are found.

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(1)

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(b) What is one economic use of plant stem cells?

Tick one box.

To create genetically modified crops

To create new species of plants

To increase variation in plants

To produce large numbers of identical plants

(1)

Embryonic stem cells divide by mitosis.

Figure 1 represents a cell cycle for a human embryonic stem cell.

Figure 1

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(c) The mass of DNA in the cell at the start of the cycle is 6 picograms.

A picogram is 10−3 nanograms.

Convert 6 picograms to grams.

Give your answer in standard form.

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Mass = _____________________ g

(1)

(d) The time taken for this complete cell cycle is 15 hours.

Calculate how many hours the cell spent in mitosis.

Give your answer to 3 significant figures.

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Time spent in mitosis = _____________________ hours

(2)

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(e) Describe what happens in each of the three stages of the cell cycle.

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(5)

(f) Figure 2 shows how embryonic stem cells are produced in therapeutic cloning for use inpatients.

Figure 2

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Give two advantages and two disadvantages of therapeutic cloning in medical treatments.

Use Figure 2 to help you.

Advantage 1 ________________________________________________________

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Advantage 2 ________________________________________________________

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Disadvantage 1 ______________________________________________________

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Disadvantage 2 ______________________________________________________

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(4)

(Total 14 marks)

This question is about cell structures.

(a) Draw one line from each cell structure to the type of cell where the structure is found.

Cell Structure Type of cell where the

structure is found

Nucleus Prokaryotic cells

Permanent vacuole Plant cells only

Plasmid Eukaryotic cells

(2)

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(b) Figure 1 shows a plant cell.

Figure 1

What are the names of structures A, B and C?

Tick one box.

Structure A Structure B Structure C

Chloroplast Vacuole Cell wall

Nucleus Chloroplast Cell membrane

Vacuole Mitochondrion Cell membrane

Vacuole Ribosome Cell wall

(1)

A student observed slides of onion cells using a microscope.

Figure 2 shows two of the slides the student observed.

Figure 2

The cells on the slides are not clear to see.

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(c) Describe how the student should adjust the microscope to see the cells on Slide A moreclearly.

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(1)

(d) Describe how the student should adjust the microscope to see the cells on Slide B moreclearly.

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(2)

(e) The student made the necessary adjustments to get a clear image.

Figure 3 shows the student’s drawing of one of the cells.

Figure 3

The real length of the cell was 280 micrometres (µm).

Calculate the magnification of the drawing.

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Magnification = × _________________________

(3)

(Total 9 marks)

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Cells divide in a series of stages called the cell cycle.

Stage 2 of the cycle is mitosis.

The diagram below shows a simplified cell cycle for a human body cell.

7

(a) Draw one line from each stage in the cell cycle to what happens during that stage.

Stage in the cell cycle What happens during that

stage

Stage 1 Nucleus divides

Stage 2 Cell divides into two

Stage 3 Copies of the DNA are made

(2)

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(b) The mass of DNA in a human body cell at the start of the cell cycle is 6 picograms.

What mass of DNA will be in each of the new cells produced by this cell division?

Tick one box.

3 picograms

6 picograms

9 picograms

12 picograms

(1)

(c) Stem cells are undifferentiated cells.

Which statement about stem cells is correct?

Tick one box.

Animal stem cells are found in meristems

Animal stem cells divide by meiosis

Meristem cells in plants can differentiate throughout the life of theplant

Meristem cells in plants can only differentiate into one type of cell

(1)

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Stem cells from human embryos can differentiate into most types of human cell.

Research is being done into the use of embryonic stem cells in medical treatments.

The long-term effects of using embryonic stem cells in patients are not well understood.

In therapeutic cloning, human embryos are produced using a donated human egg cell and a cellfrom the patient.

• The embryo produced contains the same genetic information as the patient.

• Stem cells are taken from the embryo and stimulated to divide to form cells the patientneeds.

• The embryo is then destroyed.

(d) Suggest two advantages of therapeutic cloning.

1. _________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

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(2)

(e) Suggest two disadvantages of therapeutic cloning.

1. _________________________________________________________________

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2. _________________________________________________________________

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(2)

(Total 8 marks)

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